[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180553
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
153 AM EDT Tue Aug 18 2020

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0500 UTC.

...SPECIAL FEATURES...

A broad 1009 mb low near 11N36W is along a tropical wave that is
moving W at 15-20 kt. This location is about 690 nm WSW of the
Cabo Verde Islands. The system is producing a concentrated area
of showers and tstorms displaced to the west of an elongated
surface circulation. Scattered moderate to strong convection is
seen from 09N-14N between 34W-42W. Environmental conditions are
conducive for development, and a tropical depression is likely to
form within the next day or two. The chance of tropical cyclone
formation within 48 hours is high. This system may approach the
vicinity of the Leeward Islands by late Friday or early Saturday.
Please refer to the latest NHC Tropical Weather Outlook at
www.hurricanes.gov for more details.

...FAR EASTERN ATLANTIC GALE WARNING...

A small area of gale force NE winds was occurring at 18/0000 UTC
within about 60 nm of the coast of Morocco in the marine zone
Agadir. Since that time, the gales have ended, and the gale
warning has expired as of 18/0300 UTC. Please see the latest
High Seas forecast from Meteo France at
http://weather.gmdss.org/bulletins/METAREA2.HIGH_SEAS_FORECAST.20
07.1720073740959.html
for additional information.

...TROPICAL WAVES...

A tropical wave has its axis along 27W from 02N-21N, moving
westward at about 15 kt. This wave is moving through a moist
surrounding environment. Scattered moderate to strong convection
is within 180 nm west and 60 nm east of the wave axis from
09N-13N. Over the next couple of days, this wave is forecast to
approach the tropical wave mentioned above in the Special
Features section.

A tropical wave is moving through the Lesser Antilles with axis
along 61/62W from 05N-21N, moving W at 20 kt. Scattered to
numerous strong convection is seen over NE Venezuela to the SW
part of Trinidad and the waters west of Trinidad. Scattered
moderate convection is elsewhere within 90 nm W and within 210 nm
E of the wave axis south of 16N, including over the Windward
Islands. Latest ASCAT pass shows fresh to strong winds east of
68W and north of 13N. Locally heavy rainfall and gusty winds are
expected to continue over portions of the Windward and southern
Leeward Islands through the morning hours today. This wave is
expected to continue moving quickly W over the eastern and
central Caribbean Sea during the next couple of days, which is
likely to limit significant development. After that time, the
system is forecast to move more slowly westward across the
western Caribbean, where upper-level winds could become more
conducive for the development of a tropical depression during the
latter part of this week. The chance of development within the
next 48 hours is low.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of Mauritania,
Africa near 20N16W southwestward to 13N25W and continues westward
to 11N35W to 12N52W. Aside from the convection related to the
tropical waves described above, scattered moderate convection is
within 120 nm either side of the monsoon trough between 43W-48W.

GULF OF MEXICO...

A broad and relatively weak upper-level trough stretches from the
southeastern U.S. south-southwestward over the eastern Gulf of
Mexico. A dissipating stationary front extends from near Mobile
Alabama to near Corpus Christi Texas. Isolated showers exist
near the front near the SE Louisiana coast as well as over
portions of the NE Gulf of Mexico. The latest ASCAT pass shows
light to gentle winds across most of the basin.

The stationary front from near Mobile to Corpus Christi Texas
will dissipate by early this morning. High pressure centered east
of the area will extend over the eastern and southern Gulf,
leading to light winds and slight seas. Looking ahead, the
tropical wave that is currently in the eastern Caribbean along
62W could potentially organize into a low pressure system or
tropical cyclone late this week near the NW Caribbean. Fresh to
strong winds are possible this weekend over the south central
Gulf of Mexico ahead of this potential low pressure system.

CARIBBEAN SEA...

Active weather with gusty winds is over the eastern Caribbean
between 60W-67W due to a strong tropical wave. See the Tropical
Waves section above for details.

Elsewhere across the basin, scattered moderate showers and
tstorms are noted early this morning across portions of western
Cuba and portions of Haiti due to broad upper-level troughing
over the NW Caribbean Sea. In the SW Caribbean, the east Pacific
monsoon trough is producing scattered showers and isolated
tstorms, mainly S of 13N from the Gulf of Venezuela westward.
Scattered strong convection is along the N coasts of Venezuela
and Colombia. A recent ASCAT pass shows gentle to moderate
trades over the central and western Caribbean, west of 68W.

As for the forecast, a strong and fast moving tropical wave
crossing the Windward Islands early this morning will move over
the eastern and central Caribbean Sea today through Wed, and it
has a low chance of tropical development in the next 48 hours.
Scattered showers and tstorms with gusty winds will accompany
this tropical wave as it moves W across the Caribbean. Looking
ahead, the tropical wave and low pressure system that is
currently along 35W, discussed above in the Special Features
Section, may approach the Leeward Islands by late Friday. That
system has a high chance of becoming a tropical cyclone this
week.

ATLANTIC OCEAN...

A stationary front extends from 32N76W to the Florida/Georgia
border near 31N81.5W. Scattered moderate showers and tstorms
are south of the front and north of the Bahamas, with isolated
showers over the Bahamas. Surface highs of 1016 and 1021 mb
are near 29N72W and 30N56W, respectively. In between the two
highs, a surface trough extends from 30N68W to 22N70W.
Moderate to locally fresh SE winds are seen within 120 nm E of
the surface trough. An upper-level low centered near Bermuda
is enhancing scattered moderate convection from 28N-32N between
62W-69W. Fresh to strong winds associated with the eastern
Caribbean tropical wave are affecting Atlantic waters from
14N-20N between 56W-66W. Farther east, a surface ridge prevails
along 30N, with fresh trades from 15N-23N between 30W-50W.
Strong NE winds are within 210 nm of the coast of Africa north
of 20N, with near gales north of 30N near the coast of Morocco.

As for the forecast, high pressure centered over the central
Atlantic will dominate weather this week over the western
Atlantic north of 22N, bringing gentle to moderate mainly
southerly winds to the area. A low pressure along a tropical
wave over the central tropical Atlantic is likely to develop
into a tropical depression within a couple of days, then move
to near the northern Leeward Islands by Sat.

$$
Hagen
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